Single lung ventilation (intubation) and anesthesia have been practiced for many years. Single lung ventilation has been used for surgical and non-surgical procedures. Usually single lung ventilation is used during thoracic surgery.
Single lung ventilation is indicated when there is a need to prevent spillage of blood, pus, and/or infected material from a diseased lung to a healthy lung. Most thoracic surgeries are performed by placing the patient on his or her side. The disease lung is oriented such that it is on top of the healthy lung. This surgical position significantly increases the risk of contaminating the healthy lung with blood, pus, and/or other infected material by means of gravity from the diseased lung. Therefore effective isolation of the diseased lung is required.
Single lung ventilation is also indicated during the following surgical procedures: acute and chronic bronchial pulmonary fistula and removal of one lobe of a lung with sleeve resection.
Single lung ventilation and/or anesthesia is indicated when it is necessary to provide optimal surgical exposure. Optimal surgical exposure is achieved by not ventilating the diseased lung. This is also sometimes called "quiet" collapsed lung. This technique is used during lung resection, surgery on the esophagus and/or surgery on part of the aorta.
There are also non-surgical indications for use of single lung ventilation. For example, in certain intensive care treatments it is necessary to provide selective ventilation. Indication for such non-surgical single lung ventilation are acute respiratory failure and large chronic bronchopleural fistula.
There are several devices that are available for single lung ventilation. There is a class of devices called bronchial blockers which accomplish single lung ventilation. However, these devices are not satisfactory for all circumstances. The bronchial lockers have one common feature. They are all supplied with narrow lumen inflatable balloon tipped catheters which can be selectively placed in a desired lung. These narrow lumens are prone to blockage by blood, pus, etc. from the diseased lung. It is quite common during surgery that ventilation of the diseased lung is required. This cannot be done with narrow lumen bronchial blocker. The ventilation of a diseased lung when a narrow lumen bronchial blocker is used requires the deflation of the balloon cuff which secures the catheter in place. Once the endobronchial balloon cuff is deflated and/or repositioned an effective seal/isolation of the diseased lung is lost. This permits the spillage of blood, pus, and infected material to the healthy lung.
A second class of devices, single lumen endobronchial tubes, are known and used for single lung ventilation. These devices are used to isolate and ventilate one lung while surgery is performed on the other lung. These devices are supplied with two inflatable cuffs, a tracheal cuff and an endobronchial cuff. These devices are structurally simple but have major disadvantages. If and when it becomes necessary to inflate and ventilate the collapsed lung during anesthesia, the endobronchial tube has to be removed and repositioned subsequently. This allows a situation where blood, pus, and infected material may spill into the healthy lung. Additionally, when the ventilation has been accomplished, the endotracheal tube and cuffs need to be repositioned into the patient to complete administration of anesthesia. This is difficult during surgery when the patient is in the lateral position (i.e. on his side).
Additionally, when using single lumen endobronchial tubes to ventilate the right lung, it is extremely difficult to position the endobronchial tube and attendant cuff. Anatomically the distance between the bronchus supplying the right upper lobe and the tracheal bifurcation ms very short, usually 1.5 centimeters or less. This creates a situation where after placement of the endobronchial tube in the right main bronchus, either the outlet for the bronchus supplying the right upper lobe is occluded or the endobronchial tube goes beyond the outlet for the bronchus. This creates ventilation problems and does not permit the use of the entire right lung. This causes an increased incidence of hypoxia during surgery.
A third class of devices, double lumen endobronchial tubes, are known and used for single lung ventilation. The double lumen endobronchial tubes available are bulky and require considerable operator skills to properly position the tubes in the patient. The available double lumen endobronchial tubes have two narrow lumen tubes oriented side by side and two cuffs, an endobronchial cuff and a tracheal cuff.
U.S. Pat. No. 4,453,545 to Inoue discloses an endotracheal tube with a movable endobronchial blocker for one lung anesthesia. See, for example, FIG. 3-a of the '545 patent. Also, see FIG. 1-a of the '545 patent which illustrates a conventional single lumen endobronchial tube; and, see, FIG. 2 of the '545 patent which illustrates a conventional double lumen endobronchial tube. U.S. Pat. No. 4,453,545 to Inoue discloses at column 3, lines 10-35, the manner in which the Inoue invention is positioned in either lung.
The Inoue invention (U.S. Pat. No. 4,453,545) has the disadvantages of (1) being difficult to insert; and (2) it has a narrow, endobronchial lumen. Although the combined endobronchial tube and tracheal tube of Inoue (the '545 patent) as shown in FIG. 3-a thereof may be left in the patient if bilateral ventilation is required, Inoue is nonetheless disadvantaged by the difficulty of repositioning the endobronchial tube. The endobronchial tube of Inoue must be repositioned to increase the flow area during bilateral ventilation. Further, the endobronchial tube of Inoue is too narrow and is susceptible to blockages and the like.